<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>轨迹球插件（trackball）增加对模型的交互功能</title>
    <style type="text/css">
        html, body {
            margin: 0;
            height: 100%;
        }
 
        canvas {
            display: block;
        }
 
    </style>
</head>
<body onload="draw();">
 
</body>
<script src="https://cdn.bootcdn.net/ajax/libs/three.js/r128/three.js"></script>
<script src="./js/controls/TrackballControls.js"></script>
<script>
    var renderer;
    function initRender() {
        renderer = new THREE.WebGLRenderer({antialias:true});
        renderer.setSize(window.innerWidth, window.innerHeight);
        document.body.appendChild(renderer.domElement);
    }
 
    var camera;
    function initCamera() {
        camera = new THREE.PerspectiveCamera(45, window.innerWidth/window.innerHeight, 1, 10000);
        camera.position.set(0, 0, 500);
    }
 
    var scene;
    function initScene() {
        scene = new THREE.Scene();
    }
 
    var light;
    function initLight() {
        scene.add(new THREE.AmbientLight(0x404040));
 
        light = new THREE.DirectionalLight(0xffffff);
        light.position.set(1,1,1);
        scene.add(light);
    }
    
    function initModel() {
        var map = new THREE.TextureLoader().load("./img/1.jpg");
        var material = new THREE.MeshLambertMaterial({map:map});
 
        var cube = new THREE.Mesh(new THREE.BoxGeometry(100, 200, 300, 1, 1, 1), material);
        scene.add(cube);
    }
 
    //用户交互插件 鼠标左键按住旋转，右键按住平移，滚轮缩放
    var controls;
    function initControls() {
        controls = new THREE.TrackballControls( camera ,renderer.domElement);
        //旋转速度
        controls.rotateSpeed = 5;
        //变焦速度
        controls.zoomSpeed = 3;
        //平移速度
        controls.panSpeed = 0.8;
        //是否不变焦
        controls.noZoom = false;
        //是否不平移
        controls.noPan = false;
        //是否开启移动惯性
        controls.staticMoving = false;
        //动态阻尼系数 就是灵敏度
        controls.dynamicDampingFactor = 0.3;
        //未知，占时先保留
        //controls.keys = [ 65, 83, 68 ];
        controls.addEventListener( 'change', render );
    }
    
    function render() {
        renderer.render( scene, camera );
    }
 
    //窗口变动触发的函数
    function onWindowResize() {
 
        camera.aspect = window.innerWidth / window.innerHeight;
        camera.updateProjectionMatrix();
        controls.handleResize();
        render();
        renderer.setSize( window.innerWidth, window.innerHeight );
 
    }
 
    function animate() {
        //更新控制器
        controls.update();
        render();
        requestAnimationFrame(animate);
    }
 
    function draw() {
        initRender();
        initScene();
        initCamera();
        initLight();
        initModel();
        initControls();
 
        animate();
        window.onresize = onWindowResize;
    }
</script>
</html>